Rydberg atoms and molecules: from atom and molecule optics to precision spectroscopy

Rydberg states are electronically excited states, the spectral position of which can be described by Rydberg’s well-known formula [1]. The physical properties

Rydberg
states are electronically excited states, the spectral position of which can be
described by Rydberg’s well-known formula [1]. The physical properties of these
states become very unusual at high values of the principal quantum number n [2]:Their polarizability scales as n7, the van der Waals
interaction between two Rydberg atoms or molecules as n11, the maximal electric dipole that can be induced by
an electric field as n2,
the threshold field for field ionization as n-4,
the spacing between adjacent states of a given Rydberg series as n-3, the absorption cross
section from the ground state as n-3,
the transition moment between neighboring Rydberg states as n2, their lifetime as n3, etc. These physical
properties and their rapid variation with n
form the basis of a growing number of applications of Rydberg states in
chemistry and physics. The talk will begin with an overview of the properties
of Rydberg states and their applications in physics and chemistry. I shall then
present two specific applications of Rydberg states my group is interested in.
In the first, we exploit the large dipole moments of Rydberg states to control
the translational motion of atoms and molecules, and develop methods to accelerate,
focus, deviate and reflect beams of atoms and molecules, the latest experiments
being carried out near the surface of chips [3,4]. In the second, we use
Rydberg states to carry out precision measurements of dissociation and
ionization energies of molecules to test quantum electrodynamics calculations
in small molecular systems such as H2 and He2 [5].